Green polyazo-dyestuffs



United States Patent The present iniiiao fi relates to valuable new green.

polyazo-dyestuffs and to a process for preparing the 66k. I I

same; more particiilaily it relates to azo-dyestufis corresponding to the following general formula wherein the diphenyl nucleus may contain substituents, R repres'eiits the radical of an aryl. sulfonic acid; R represents a radical of the benzene or naphthalene series, one Z stands for the OH-group and the other Z stands for the NH -group.

' I have found that vividgree'ri polyazo dyestufls, which are especially suitable for dyeing all kinds ofleather, are obtained by coupling in any order of succession 1 2 l'-arnino-8 hydroxynaphthalene-3,6-dis1ilfonie acid. The diaioazo compound so obtained is coupled in a sodaalkaline medium with the diazolcornpound from 20.3 parts of 1-amino-Z-methoxybenzene-S-sulfonic acid. A solution alkaline with caustic soda from 25.7 parts of 1 acetoacetylaminobenieriee l-sulfonic acid is run into the diaiodisazo-compoundso obtained. The green trisazodyestuff is rapidly formed. After 2 hours the solution is rendered acid with mineral acid and heated to 85 C The dyestufl is then precipitated with sodium chloride, filtered offwith suction and dried. It is a black powder which dissolves in water to give an emerald green solution and. dyes leather beautiful yellowish green tints of ggod general fastness properties. The dyestufi corresponds to the following formula:

Instead of 1-aminoe2-methoxybenzene-5-sulfonic acid there may also be used other sulfonated or unsulfonated amines, such as 1-amino-4-nitrobenzene-2-sulfonic acid,

mol of the tetra'id compound from a diaminodiphenyl.

which may contain substituents in both nuclei, and 1' idol of a diazocompor rnd of v the benzene or naphthalene series with l mol 6f 1 airiinb hydroiiynaphthalne-3,6 disulfonic a'cidoi- 1-amino-8-hydroxynaphthalenee4,-di sulfoiiic acid and combining the diazodisazo-compo'und so obtained with 1 mol of an acetoacetylaminoaryl sulionic acid obtainable for example by diketenizing an aromatic amino-sulfonic acid which may contain further substituents. y, p v

The new dyestufis dye leather very uniform green tints which possess a good fastness to washing and a very good resistance to acids, alkali's and formaldehyde. On account of their good penetrating properties they are especially suitable for dyeing velvet leather which does not lighten when it is subsequently buffed.

As compared with the trisazo-dyestufis described in German Patent No. 737,626 which are prepared with the use of unsulfonated acetoacetic acid arylamides as end components, the dyestuffs of the present invention are distinguished by an improved solubility even in cold water so that they are suitable for brush dyeing from a cold bath.

The following examples illustrate the invention, but they are not intended to limit it thereto, the parts being by weight.

Example 1 18.4 parts of benzidine are tetrazotized and coupled in a weak mineral acid solution with 31.9 parts of amino-4-methoxybenzene. 'dye leather yellowish to bluish green tints of good gen- 1-amino-4-methylbenzene-3-sulfonic acid, l-aminonaphthalene-6 (7 -sulfonic acid, 1-amino-4-acetylaminoben- Zene-Z-shlfoiiic, acid, l amin o-l-rnethyl chlorobenzene- S-sulfonic acid, aniline, 1-amino-4-ni'trobenzene or 1'- The dyestuffs so obtained eral fa stness properties.

When in the above example the acetoacetyl compound of 1-aminobenzene4-snlfonic acid is replaced by the acetoacetyl compounds of 1-aminobenzene-2-sulfonic acid, 1-arninobenzene-3-sulfonic acid, 1-amino-4-methylbenzene-S-sulfonie. acid, 1-amino-8-hydroxynaphthalene- 3,6 cli sulfo'riic acid, Z-airiiiho-5-hydroxyrlaphthalenefl slil fonic acid, 4-aminodiphenylamine-Z-sulfonic acid, 1- aminonaphthalene-6(7)-sulfonic acid, or by the diacetoacetyl compound of 4,4'-diaminodiphenyl-2,2-disulfonic acid, readily soluble dyestuffs are obtained which dye leather likewise yellowish to bluish green tints of good fasthess properties;

Wheri- 1-amino 8-hydroxynaphthalene 4,6 disulfonic acid is used instead of l-amino-8-hydroxynaphthalene- 3,6-disulfonic acid or the benzidine is replaced by 4,4- diamin0-3,3'-dichlorodiphenyl, there are obtained green dyestuffs possessing a somewhat improved fa-stness to light.

Example 2 25.3 parts of 1 arninobenzene-iz,S-disulfonic acid are diazotized and coupled in a weak mineral acid medium with 3.1.9 partstof 1-amino-8-hydroxynaphthalene-3,6-disul foiii c acid. When the coupling is complete, there is added drop by drop a tetrazo solution from 18.4 parts of benzidine in a soda-alkaline medium. As soon as the diazodisazo-compound is formed, a caustic-alkaline solution of 25.7 parts of 1-acetoacetylaminobenzene-4-sulfonic acid is run in. The trisazo-dyestuff is rapidly formed. The solution is stirred for a further 2 hours, then adjusted with hydrochloric acid to a pH-value of 2, heated to C. and the dyestufi is prec pitated by the addition of sodium chloride. It is filtered off with suction and dried. A black powder is obtained which dissolves very readily even in cold water to give a dark green solution and dyes leather very vivid green tints mater Dec. 27, 196%) a 4 of good fastness properties. The dyestuif corresponds phenyl. The dyestuffs so obtained'dye leather likewise to the following formula: green tints which possess good fastness properties.

CH: s0=H NH, 011. l

CO-NH-O-SOzH s ,H Ross S0 H Instead of 1-aminobenzene-2,S-disulfonic acid there I claim: may also be used other amines the diazo compound of 1. The polyazo-dyestuff corresponding to the followwhich is active enough to couple with 1-arnino-8-hydroxying formula CH1 OCH: 0H NE: (E

ho-NH-Osoirr SOsH H033 SO1H naphthalene-3,6-disulfonic acid in a mineral acid medium. 2. The polyazo-dyestuif corresponding to the follow- The procedure described in Example 2 enables to use ing formula OH: OCH; 0H NH: 4;

c w-NnOsmn SOsH Roam substituted benzidines which according to experience can 3. The polyazo-dyestufi corresponding to the followonly difiiculty be coupled completely on one side in ing formula OH: OCH: OH NH: Q QC? f N=N =N N=N H m eo-NH-Osom SOsH H0: S0;H c1 1 an acid medium, such as 4,4'-diamino-3,3'-dimethoxydi- 4. The polyazo-dyestufi corresponding to the following formula CH; OCH: (311 11TH:

| JJO-NH SOaH H01 SOzH References Cited in the file of this patent UNITED STATES PATENTS 2,202,350 Lier May 28, 1940 FOREIGN PATENTS 737,626 Germany July 20, 1943 r 

1. THE POLYAZO-DYESTUFF CORRESPONDING TO THE FOLLOWING FORMULA 